disturbances , known as the Cushing ’ s triad ( Leece , 2016 ). Immediate treatment of such cases should be initiated , targeted on decreasing the ICP and maintaining cerebral perfusion pressure ( CPP ) rather than treating the secondary cardiovascular effects ( Leece , 2016 ). It is worth noting that treatment options can include the use of mannitol and / or hypertonic saline fluid therapy ( Ballocco et al ., 2019 ), but these should only be used following veterinary instruction / prescription .

Recovery considerations and precautions

A smooth recovery from anaesthesia is desirable in order to limit stress and associated catecholamine release , which can increase the patient ’ s mean arterial pressure ( MAP ), elevating ICP ( Armitage-Chan et al ., 2007 ). Minimising the patient ’ s response to extubation is important ; excessive stimulation and leaving the endotracheal tube ( ETT ) in place too long can cause coughing and hypertension ( Raisis & Musk , 2013 ), and should be avoided . It is equally as important to ensure the patient is able to adequately ventilate and maintain normocapnia prior to extubation . Patients should be recovered in a warm , calm , quiet room with the lights dimmed , and with adequate sedation and analgesia provided , in order to reduce any stress , anxiety or pain .

Raisis and Musk ( 2013 ) provide guidelines for the recovery and extubation time-period for patients with intracranial disease ( Table 1 ).

Conclusion

Table 1 . Recovery and extubation guidelines for patients with intracranial disease .

Step

Guideline

1 Move patient to a quiet , warm environment with minimal noise and stimulation before discontinuing anaesthetic .

2 Prepare for extubation : untie the ETT ; have cuff syringe available to deflate the cuff ; have additional ETT and anaesthetic agents ready for reintubation , if necessary .

3 Discontinue anaesthetic and monitor closely for clinical signs suggesting reducing depth of anaesthesia : return of palpebral reflex , increasing heart rate and arterial blood pressure .

4 Attempt a short period of trial apnoea (< 1 minute ). Do not allow ETCO ₂ to exceed 45 mmHg .

5 If spontaneous breathing does not occur , continue ventilation .

6 Continue to repeat short periods of apnoea intermittently until spontaneous ventilation returns .

7 Once spontaneous ventilation returns , use capnography to monitor adequacy . If ETCO ₂ is > 45 mmHg , resume ventilation . If ETCO ₂ is maintained below 45 mmHg , extubate .

8 Monitor for patency of airway and continued ventilation .

The VN plays a vital role in the anaesthetic management of patients with intracranial disease . Knowledge and recognition of both causes and clinical signs of elevated ICP are important when communicating with the veterinary surgeon , in order to create an appropriate anaesthetic plan and allow safe monitoring / management of the case . Minor adjustments ( such as harness walks only ) can be implemented into the patient ’ s nursing care plan , which can minimise the chances of ICP worsening . Most importantly , the nurse ' s role is critical in recognising the overall aims before anaesthetising such a patient : to establish an airway , ensure adequate ventilation , support the cardiovascular system and control ICP as much as possible ( Raisis & Musk , 2013 ).

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